UGC NET Questions (Paper – 1)

Methane is a potent greenhouse gas released from the digestive systems of ruminant animals and from anaerobic decomposition in flooded rice fields. Agriculture is a major source of this gas globally. The stem specifically mentions livestock fermentation and flooded paddy fields,which are classic methane sources. Therefore “methane” is the correct answer.

Option A:
Carbon dioxide is the dominant greenhouse gas from fossil fuel combustion,but it is not the main gas from enteric fermentation or flooded paddies.

Option B:
Nitrous oxide is emitted mainly from fertilised soils and manure management; it is important but not the key gas from the two sources named in the stem.

Option C:
Ozone is a secondary pollutant formed in the atmosphere; it is not directly emitted from livestock digestion or flooded rice fields as described.

Option D:
Methane is directly produced in anaerobic conditions and ruminant digestion,which matches the exact sources stated in the question.